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Project information
»Funding dates
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Original grant (2001-2005)
Yr 1: 12/1/2001-11/30/2002
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First renewal (2005-2009)
Yr 5: 12/1/2005-11/30/2006
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Yr 2: 12/1/2002-11/30/2003
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Yr 6: 12/1/2006-11/30/2007
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Yr 3: 12/1/2003-11/30/2004
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Yr 7: 12/1/2007-11/30/2008
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Yr 4: 12/1/2004-11/30/2005
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Yr 8: 12/1/2008-11/30/2009
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Rice field experiment on iron
toxicity. |
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»The problem
Southeast Asian farmers living in relatively homogeneous rice-growing
environments, where controlled irrigation and good access
to fertilizer inputs are the norm, have realized tremendous
production gains from the introduction of high-yielding rice
varieties (HYVs) developed by national and international rice
breeding programs. However, irrigation covers only 12% of
Cambodia's rice land, 23% in Laos, and less than 30% of Thailand.
The majority of rice farmers in these countries live in more
highly variable production environments (mountainous uplands,
small foot-hill valleys, flood-plains, etc) and have benefited
less or not at all from the products of scientific breeding
programs. Farmers in these traditional rice cropping systems
have preferred to rely on their local, genetically-diverse
rice varieties, which they knowledgeably deploy in combination
with modern and traditional inputs. In effect, these farmers
are now maintaining much of the world's remaining diversity
in rice germplasm in their production fields.
Traditional rice cropping systems are also under pressure
to increase rice productivity to meet the food and economic
needs of rapidly growing populations. However, increased rice
productivity in these systems is currently constrained by
a host of complex and often interrelated stress factors, including
extremes of temperature and/or water-availability, unfavorable
soil chemical conditions, and yield loss attributable to key
rice pests, such as gall midge, rice blast, and invasive,
weedy rice. The previously funded CCRP project, "Agrobiodiversity
for in situ conservation and management of Thailand's native
rice germplasm" (2001-2005), undertook an in-depth study
of the local varieties grown in traditional rice cropping
systems across a wide range of environments in Thailand. The
project team concluded that (1) improved understanding and
management of the tremendous genetic diversity found in farmers'
local varieties, combined with some fine-tuning of key agronomic
practices, holds the key to increased productivity in these
systems and that (2) working with farmers to make strategic
improvements in their methods of selecting and transferring
seeds amongst themselves is a more effective strategy for
meeting farmers' needs and production niches than turning
promising varieties into single genotype 'improved' varieties.
»The approach
This project will extend the key findings and capacities built
in the previously funded project to similar rice cropping
systems in neighboring Cambodia and Lao PDR, as well as in
other parts of Thailand that were not reached earlier. Farmers
in these new target areas face many of the same production
constraints, as well as opportunities for improvement, that
were identified during the earlier project, when the research
team studied varietal adaptations and improved management
practices across a diverse range of production environments.
A successful integrated approach to weedy rice control was
developed in the first phase of the project and a number of
genetic traits were studied in detail, including gall midge
resistance, tolerance to blast, tolerance to soil acidity,
adaptation to rainfed conditions (alternating wet and dry),
association with arbuscular mycorrhizal fungi, grain Fe content
and bioavailability, and grain milling and cooking quality.
Many findings from the previous project, especially those
related to gall midge resistance and weedy rice control, are
likely to be directly applicable in Cambodia and Laos. Other
locally-important problems and opportunities in the two new
target countries have been identified and will be verified
during the first year when baseline information is established.
The newly constituted project team, which incorporates new
partners in Cambodia and Laos, will continue to take the three-pronged
research approach they developed earlier, namely conducting
(1) basic research aimed at characterizing the structure and
dynamics of genetic diversity found in the cultivated and
wild rice populations in the new target areas; (2) adaptive
farmer participatory research aimed at evaluating and verifying
the potential of various management practices to contribute
to improved rice productivity and conservation of local germplasm;
and (3) interdisciplinary research aimed at elucidating the
complex socio-cultural, economic and biological factors that
impact farmers' traditional rice seed systems.
Theme
1
Phylogeography of Asian wild rice, Oryza rufipogon,
reveals multiple independent domestications of cultivated
rice, Oryza sativa. By Jason P. Londo, Yu-Chung Chiang,
Kuo-Hsiang Hung, Tzen-Yuh Chiang, and Barbara A. Schaal. PNAS
103(25): 9578;8211;9583 (June 20, 2006)
Theme
2
Invasion of weedy rice in rice fields in Thailand: problems
and management. By Chanya Maneechote, Sansanee Jamjod and
Benjavan Rerkasem. International Rice Research Notes 29(2):
14-16. (December 2004)
Theme
3
Varietal Turnover and Seed Exchange: Implications for Conservation
of Rice Genetic Diversity On-Farm (Awarded first prize in
Genetic Resource Category for the International Year of Rice).
By Anothai Sirabanchongkran, Kanok Rerkasem, Narit Yimyam,
Warapong Boonma, Kevin Coffey, Miguel Pinedo-Vasquez and Christine
Padoch. International Rice Research Notes 29(2): 18-20. (December
2004)
»The goals
To develop strategies to improve the productivity of traditional
rice cropping systems that are compatible with in situ
conservation of rice genetic diversity; to develop the interdisciplinary
capacity to accomplish this within and near the centre of
rice genetic diversity in Cambodia, Laos, and Thailand.
»Back to top
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Measuring the effect of iron
toxicity, Vientiane, Laos. |
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Project impact
Weedy rice is emerging as a serious threat to rice farming
in Asia. Its invasiveness enhanced by several recent changes
in the rice production system. Farmers' fields can be overtaken,
and their crops rendered valueless, within three to four crops
after an initial invasion. The  Rice
biodiversity (Southeast Asia) project team has conclusively
shown that weedy rice is the product of hybridization between
cultivated rice (Oryza sativa) and its ubiquitous wild
relative (O. rufipogon). The team has developed strategies
for the integrated management of weedy rice. They have demonstrated
the effectiveness of these strategies with local farmer cooperators
and have made the information available on a national scale.
In response to rising labor cost that comes with Asia's economic
growth, direct seeding is rapidly replacing transplanting.
Mechanical harvesters spread weedy rice seed over long distances
as well as from field to field. Instead of flowering and producing
seed once a year like traditional rice varieties and local
wild rice, weedy rice produces seed year round just like photoperiod
insensitive modern rice varieties. Weedy rice therefore propagates
every time a rice crop is grown, which may be as often as
five to seven times in two years in Asia's irrigated and most
productive rice land. Weedy rice is formidably noxious as
it seems to have inherited the high reproductive capacity
from modern rice varieties, and seed shattering and dormancy
of wild rice, which contribute towards build up and persistence
of its seed bank in the soil.
As the degree of weedy rice infestation increases, rice yield
declines in direct proportion: farmers lose 1.1% of yield
for every 1% increase in infestation. Although the effect
on yield at low level infestation of 5-15% may be imperceptible,
contamination of red rice, crumbly endosperm and spikelets
with awn or off-type shape, size or color may all result in
price deduction. By the time infestation reaches 40%, yield
is about halved, and with 80-90% infestation the entire crop
is lost.
From light infestation of 5-10%, farmers who carry on with
routine crop management, which includes application of selective
rice herbicides, find their fields completely taken over by
weedy rice within three to four crops.
Research from the CCRP's Thai Rice Biodiversity project has
contributed to understanding in biology and ecology of weedy
rice, and how these interact with farmers' management of the
rice crop to influence invasiveness. A suite of management
practices has been developed, based on this understanding
and in collaboration with farmers, for integrated control
of weedy rice. Through these, the project has made impact
on rice farming in Thailand at two levels. First is direct
impact on the reduction of losses in rice yield due to weedy
rice for collaborating farmers in Kao Sam Sib Harb, Kanchanaburi,
and their neighbours in the same and nearby villages and provinces.
Second is Thailand's national rice research system.
In the neighborhood of Kao Sam Sib Harb, modern high yielding
rice varieties are grown twice a year with irrigation high
inputs; yields without the weedy rice average about six tons
per hectare per crop. Through project intervention, farmers
now are able to keep the weedy rice under control and prevent
the yield loss. Understanding of the key biological and ecological
processes and crop management practices important to weedy
rice control is being integrated into the local knowledge
base about rice farming. For example, farmers are now aware
that weedy rice seed can be transferred into their own fields
from a neighbor's heavily infested field by the combined harvester
or in seed contaminated with weedy rice. They know that weedy
rice seed is unlike cultivated rice seed in that it becomes
viable even while in milky stage and can stay viable for a
long time buried in the soil and mud. It is now also common
knowledge in the area that it takes only three to four crops
for a few panicles of weedy rice per m2 to take over the entire
field. Malai Semtap, a Kao Sam Sib Harb collaborating farmer,
said "When there were just a few of them (weedy rice
panicles), I sat around twiddling my toes. Suddenly the crop
is overwhelmed. We really need to control the weedy rice even
when it looks quite harmless."
The project is responsible for weedy rice being recognized
as a national problem, and our contribution in biological
and ecological understanding provides the basis for research
and extension initiatives to control it from the public (Plant
Protection Research and Development Office of the Department
of Agriculture and Department of Agricultural Extension) private
sector. The emergence of weedy rice, reinforced by the project's
results in explaining the role of cultivated and wild rice
hybridisation, is also beginning to be perceived as the context
in which transgenic and other genetic manipulation of rice
are to be evaluated. We have been requested to provide technical
information on potential impact of transgenic rice on the
local rice germplasm, including wild and weedy rice in two
national forums.
»Back to top
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The project team at Chiang Mai University put on a poster display in the garden. |
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Investigators
»Partner institutions
»Investigators at CMU
(*=project leader)
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Benjavan Rerkasem*
Kanok Rerkasem
Sansanee Jamjod
Chanya Maneechote
Amena Prommin
Anothai Sirabanchongkran
Ariya Paokrueng
Athitya Suta
Anupong Wongtamee
Ayut Kongpan
Chanakan Prom-u-thai
Chopetch Saenchai
Chonticha Tawilprai
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Janjira Mongon
Jumnian Wongmo
Kwanchanok Patison
Nattinee Phattarakul
Napat Somkual
Narit Yimyam
Panomwan Boonchuay
Pennapa Jaksomsak
Prateep Oupkeaw
Rataya Yanaphan
Ronnachit Jindalouang
Saengdao Kittiworawat
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Sawika Konsaeng
Suthipong Jindaluang
Sithichai Lordkaew
Suwanee Laenoi
Sunisa Niruntrayakul
Somchit Youpensuk
Therdsak Anakad
Tonapha Pusadee
Utumporn Chaiwong
Wachira Porchit
Wilailak Sommut
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»Investigators at LARC
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Kongpanh Kanyavong
Chay Bounphanousay
Khamla Phanthaboun
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Khemkham Hongphakdy
Phoumi Inthapanya
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Singty Voradeth
Vilaphong Kanyasone
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»Investigators at CARDI
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Ouk Makara
Chou Vichet
Leng Lay Hout
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Sakhan Sophany
Say Puthea
Seang Lay Heng
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»Investigators at New York
Botanical Garden
Christine Padoch
»Investigators at Columbia
University
Miguel Pinedo-Vasquez
Kevin Coffey
»Investigators at Washington
University
Barbara Schaal
»Back to top
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Annual progress reports
Click the links below for annual progress reports.
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»Original grant
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»First renewal
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Year 5 (12/2005-11/2006)
English
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Year 6 (12/2006-11/2007)
English
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Year 7 (12/2007-11/2008)
English
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Year 8 (12/2008-11/2009)
Due 12/31/2009
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»Back to top
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Publications
CCRP supported publications
File date: 4/26/2007
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